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global rs_isr
extern rsint_rx
extern rsint_tx
extern rsputs
%define RSBASE 0x3F8
%define RSDATA RSBASE
%define RSINTEN (RSBASE + 1)
%define RSFIFOC (RSBASE + 2)
%define RSINTID (RSBASE + 2)
%define RSLINEC (RSBASE + 3)
%define RSMODEMC (RSBASE + 4)
%define RSLINES (RSBASE + 5)
%define RSMODEMS (RSBASE + 6)
%define RSSCRATCH (RSBASE + 7)
rs_isr:
pusha
mov ax, ds
push ax
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov dx, RSINTID
in al, dx
test al, 1
jnz .skip
and al, 0x0E
cmp al, 0x04
je .rx
cmp al, 0x0C
je .rx
cmp al, 0x02
je .tx
jmp .skip
.tx:
call rsint_tx
jmp .skip
.rx:
call rsint_rx
.skip:
mov al, 0x20
out 0x20, al
pop ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
popa
iret
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